A patient is prescribed Flexeril (cyclobenzaprine) for muscle spasms. Which of the following is the most common side effect that the nurse should educate the patient about?

Choice A reason: This is incorrect. Polydipsia is excessive thirst, which is a symptom of hyperglycemia (high blood sugar), not hypoglycemia (low blood sugar). People with hyperglycemia lose fluid through frequent urination and become dehydrated, which makes them thirsty.

Choice B reason: This is correct. Shaking is a common sign of hypoglycemia. It occurs because the body releases adrenaline and other hormones to raise blood sugar levels. Adrenaline causes the muscles to tremble or shake.

Choice C reason: This is correct. Confusion is another common sign of hypoglycemia. It occurs because the brain does not get enough glucose, which is its main source of energy. Low blood sugar can impair cognitive functions, such as memory, attention, and judgment.

Choice D reason: This is incorrect. Tachycardia is a rapid heart rate, which can be a symptom of both hypoglycemia and hyperglycemia. However, it is not a specific or reliable indicator of low blood sugar, as it can also be caused by other factors, such as stress, anxiety, caffeine, or medication.

Choice E reason: This is incorrect. Polyuria is excessive urination, which is another symptom of hyperglycemia, not hypoglycemia. People with hyperglycemia have high levels of glucose in their blood, which draws water from the cells and increases urine output.

Choice A reason: Tinnitus is a rare side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Tinnitus is a ringing or buzzing sound in the ears that can be caused by various factors, such as ear infections, noise exposure, or certain medications. Flexeril does not affect the auditory system directly, but it can cause confusion or dizziness, which may worsen the perception of tinnitus.

Choice B reason: Drowsiness is the most common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Drowsiness occurs because Flexeril has sedative and anticholinergic properties, which means that it blocks the action of acetylcholine, a neurotransmitter that regulates arousal and alertness. Flexeril can impair the mental and physical abilities, especially in elderly patients or those who take other medications that cause drowsiness¹. The nurse should educate the patient about the risk of drowsiness and advise them to avoid driving or operating machinery while taking Flexeril.

Choice C reason: Diarrhea is not a common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Diarrhea is a condition that causes loose or watery stools, which can be caused by various factors, such as infections, food intolerance, or certain medications. Flexeril does not affect the gastrointestinal system directly, but it can cause dry mouth, nausea, or constipation, which may alter the bowel movements¹.

Choice D reason: Palpitations are not a common side effect of Flexeril, which is a medication that relaxes the muscles and relieves pain and stiffness¹. Palpitations are a sensation of rapid or irregular heartbeat, which can be caused by various factors, such as stress, anxiety, caffeine, or certain medications. Flexeril does not affect the cardiac system directly, but it can lower the blood pressure or interact with other medications that affect the heart rate, such as betablockers or antidepressants¹.